1. Field of the Invention
This invention relates to systems for determining the accuracy of wiring, component insertion, and soldering onto a printed circuit board, and particularly to an automatic means of testing for such accuracy.
2. General Description of the Prior Art
Printed circuit boards are typically checked at several stages of manufacture in order that defects can be caught at as early a stage as possible to minimize corrections that have to be made and to avoid discarding finished or near-finished boards wherein errors are caught too late for easy, and thus inexpensive, correction. This, of course, requires a considerable effort, often involving both visual and electrical inspection. The applicants have been informed that there badly exists the need for some automated system for rapidly and accurately checking boards at critical stages of production. Some of the typical problems faced in the production manufacture of these printed circuit boards are:
1. Verification of the locations (X and Y coordinates) and diameter of the perforated holes in boards.
2. Component location and identification of component.
3. Lead penetration.
4. Lead crimp direction.
5. Unintended solder bridges connecting integrated circuits or across foil.
6. Solder joint reliability.
7. Lead depth below board.
8. Cracks in printed circuit boards.
9. Foil integrity.
Ideally, there would be provided an automatic means for rapidly and accurately checking boards for one or more of the above stated conditions at selected and critical stages of production. Accordingly, it is an object of this invention to provide such a system.